The mouse glucocorticoid receptor DNA-binding domain is not phosphorylated in vivo.
The glucocorticoid receptor is phosphorylated, but the precise location of the phosphorylated groups is unknown. We cultured AtT-20 cells in medium containing [32P]-orthophosphate and used immunoaffinity methods to isolate the intact receptor and a tryptic fragment containing the DNA binding domain. Analysis of the intact receptor, co-labeled with the affinity ligand dexamethasone-mesylate, confirmed that the receptor was phosphorylated. Isolation of the DNA binding domain by trypsinization and immunopurification showed that it was not phosphorylated. Interestingly, a non-immunoreactive phosphorylated fragment similar in size to the DNA-binding fragment was observed. Our results suggest that phosphorylation of the DNA binding domain of the glucocorticoid receptor is not essential for hormone action.
van der Weijden Benjamin
W S
WS
Division of Endocrinology/Metabolism, University of Arkansas for Medical Sciences, Little Rock 72207.
Hendry
W J
WJ
Harrison
R W
RW
D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D004268:DNA-Binding Proteins / Q000378:metabolism*; D051379:Mice; D010446:Peptide Fragments / Q000032:analysis; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D014357:Trypsin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D010446:Peptide Fragments; D010750:Phosphoproteins; D011965:Receptors, Glucocorticoid; D014357:Trypsin